Does anyone else feel they lost HP when adding mufflers?

I finally got around to putting a couple Flowmaster super 10 mufflers on my charger (5.7). The sound is A+, but I feel like I lost horsepower and acceleration. Is this even possible? Or am I just trippin?! Is it a placebo effect because now she’s always roaring, and before it was only when I punched it? Need some reassurance 😅